For the past several years, the importance of terminal galactose groups in the glycoproteins in platelet interactions has been studied. It was found that platelet aggregation, adhesion and serotonin release are dependent upon the glycoproteins. The current studies include the effect of galactose-immobilized albumin on platelet adhesion and aggregation to verify the previously proposed mechanisms. Immobilized galactose contents and the length of spacer for coupling will be varied for this study. The oligosaccharide groups in the well prepared and characterized fibronection will be tested to verify whether they play an important role in the platelet adhesion on the surfaces.